Polyester resins based on fatty acids that have a short oil length, aqueous dispersions and associated coatings

ABSTRACT

The invention relates to a polyester resin which is based on at least one fatty acid, with zero oil length (0%) or an oil length of between 0 and 35%, with a weight ratio of oxidizable fatty acids (monoacids), relative to the overall fatty acids, of 0 or greater than 0 and ranging up to 1, and which is based on an acid component comprising, in addition to the fatty acid, from 30% to 85% by weight, relative to the total weight of said resin, of rosin and/or of derivatives thereof bearing at least one carboxylic acid function.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation application of U.S. application Ser.No. 13/876,222 filed Mar. 27, 2013, which is a national stageapplication under 35 U.S.C. §371 of PCT/FR2011/052208, filed Sep. 23,2011, which claims benefit to FR application FR 1003817, filed on Sep.27, 2010, which are hereby incorporated by reference in their entirety.

FIELD OF THE INVENTION

The invention relates to a fatty acid-based polyester resin, inparticular an alkyd resin, with a short or even zero oil length,modified to a high proportion by rosin or derivatives thereof, a bindercomposition based on this modified resin, more particularly an aqueousdispersion based on this resin with no presence of organic solvent, andto applications as binder in coatings and in particular in water-basedcoatings for adhesives, paints, surface coatings, primers or varnishes.This polyester resin, and in particular alkyd resin, uses a high contentof starting materials of renewable origin and has specific performancequalities, in particular concerning the development of hardness overtime after application and the reduction of yellowing. In particular,the novel resin may be used as binder in decorative or industrialwater-based coating compositions capable of curing in air with orwithout siccativating agent.

BACKGROUND OF THE INVENTION

Alkyds in organic solvent medium, also referred to as beingsolvent-based, are resins that have been known for a long time to thoseskilled in the art, and are used in general in decorative and industrialpaint formulations and coatings. To satisfy questions as regards comfortof use, odor and toxicity, specific alkyd emulsions have been developedand marketed for about 20 years, with advantageous performance levels interms of gloss, drying, appearance/color, stability and odor. Atechnical solution for conventional implementation, employed to formalkyd emulsions that are stable over time, consists in using acombination of a nonionic surfactant with an anionic surfactant asdescribed in WO 2008/076360.

Despite these improvements, certain parameters and performance levelsstill remain to be improved, such as the resistance to yellowing, theblocking resistance, the hardness, the water sensitivity and thebiodegradability. The tendency toward yellowing is a natural andintrinsic property of alkyd resins, which thus limits their use to quitespecific end uses, for instance primers, surface coatings, woods andtrims. The first alkyd emulsions described in the literature concernalkyds with large oil lengths of about 65% to 82% as described inColloids Surfaces A. Physicochem. Eng. Aspects 1995, 94, 161-171. Theemulsification of resins with a smaller oil length is relativelydifficult to perform, due to the lower affinity of surfactants with theresin, as explained in Prog. Org. Coat. 1994, 24, 281-97. Nevertheless,nowadays, commercial products have an average oil length of 50%, asdescribed in WO 2009/140192 or even a smaller oil length up toapproximately 40% for the lowest oil lengths, as described in Prog. Org.Coat. 2000, 40, 253-266 or even more recently in WO 2008/076360. For amore systematic and universal use, it is necessary to find solutionsthat guarantee products which develop less yellowing for applications ofwider scope such as on walls or ceilings. Nowadays, these applicationsare almost exclusively reserved for acrylic emulsions, which have beenknown for a long time for their good resistance to yellowing and tooxidation, but acrylic emulsions have drawbacks such as lower gloss,water sensitivity (lower water resistance) and poorer chemicalresistance.

The resin of the present invention proposes to overcome the mentioneddrawbacks of the prior art, while at the same time affording highdispersibility in water without any need for organic solvent and in theabsence of groups that make the resin self-dispersing. This capacitymakes it possible to obtain resin dispersions without any organicsolvent or protective colloids and which are stable on storage, and toobtain coatings associated with high gloss and high hardness, and, byvirtue of its hydrophobic nature, high water resistance, such as highresistance to yellowing over time. An additional advantage during thedrying of the resin dispersions according to the present invention isthe faster development over time of high, stable hardness, this beingachieved without the need for systematic addition of a siccativatingagent of cobalt type. This therefore leads to an amicable solution forman and for his environment due to the absence of organic solvents inthe dispersion and also the absence of siccativating agents on drying,but also via the choice of the essential raw materials, insofar as alarge proportion of these raw materials is of renewable and durableorigin and may also lead to chemical structures that are more readilybiodegradable. The dispersions of the invention and the coatingsresulting therefrom are thus favorable toward environmental protection,while at the same time having application qualities that are at the veryleast identical, if not improved, with respect to conventionalwater-based coatings. In addition to the environmental protection, thehighly renewable nature of said aqueous binders according to the presentinvention should be underlined, which binders are predominantly preparedfrom rosin and natural fatty substances. This advantage is appreciablesince, in certain cases, the proportion of renewable raw materialsreaches a level of 100% on the overall composition of the resin(surfactants excluded). This enables the manufacture of this novel typeof resin, which may be used as binder, by virtue especially of thedurable and seasonal availability of said raw materials. These samereasons also make it possible to limit the environmental impact via areduced carbon imprint and an improved life cycle. These two parametersreflect the impact of the manufactured products on the environment andhealth. “Renewable” or “bio-sourced” resources in particular make itpossible to reduce the emissions of greenhouse gases such as carbondioxide.

SUMMARY OF THE INVENTION

With this aim, the present invention proposes a novel range of polyesterresins based on oxidizable and/or non-oxidizable fatty acids, inparticular alkyd resins, with a greatly reduced or zero short oillength, for their dispersion in water with the aid of surfactants, andwhich are capable of substantially curing without the excessive supplyof unsaturated fatty oils or acids. These dispersions, which arecommonly known as “emulsions”, give, after application to a substrate,coatings that are stable over time and ensure low yellowing evolutionand also substantial development of hardness after application anddrying, despite having a greatly reduced or zero oil length. The verycapacity of certain resins with a very small oil length, in particularfrom 0 to 15%, to cure strongly and rapidly with the drying time, andabove all without the necessary supply of siccativating agent, is asignificant advantage in the current environmental context, Moreparticularly, in this context, the use of cobalt-free drying systems isan increasingly important need, given the increasing environmentalrestrictions on the use of cobalt as a siccativating agent.

More particularly, the resin according to the invention with a zero oillength (0%) or an oil length ranging up to 5% (meaning an oil lengthranging from 0 to 5%), in addition to its capacity to be used as a resinfor obtaining aqueous dispersions for water-based coatings, as describedabove, also has the capacity to be used as a binder resin fornon-water-based coatings and more particularly for two-packapplications, for example as “coil” coating resins for application tometal sheets. The same performance improvements as with water-basedcoatings are obtained, especially in terms of hardness and chemicalresistance, for example. The non-water-based coatings obtained with abinder resin according to the invention, having a zero oil length (0%)or an oil length ranging up to 5%, give in addition (additionalperformance) a significant improvement in the adherence to steel and inparticular to galvanized steel.

Alkyds are oligomers that are conventionally obtained bypolycondensation between diacids and polyols in the presence of a moreor less large proportion of “oil” or of “oxidizable unsaturated fattyacids”. The diacids and polyols usually used to form the polymerstructure are phthalic anhydride, isophthalic acid, pentaerythritol andglycerine (or glycerol). The number-average molecular masses Mn may thusrange between 1000 and 10 000 g/mol, as a function of the OH/CO₂H(hydroxy/carboxy) ratio used. Monoacids such as benzoic acid and rosin(mainly and predominantly containing natural resinous acids such asabietic acids including dehydroabietic acid, pimaric acids, mercusicacids and communic acids) may be added to the alkyds as acid component.These components thus make it possible to reduce the oil length and toincrease the hardness of the alkyd. On the other hand, reducing the oillength makes the resin less readily dispersible in water withsurfactants and above all without the aid of solvent. According toPaintindia, November 2007, 61-65, it is essential to use organic solventin order to facilitate the dispersion in water, but the presence of suchan organic solvent is incompatible with environmental protection asdemanded in the present invention. By reducing the oil length of certainalkyds, we have found, unexpectedly, that the rosin used under theconditions of the invention considerably facilitates the developmentover time of the hardness of the coatings, in particular alkyd coatings,thus formed during oxidative drying also known as siccativation and alsofacilitates the aqueous dispersion of the resin without any need fororganic solvent or protective colloid, The hardness associated with theobserved curing of the resin increases over time after application ofthe coating composition and offers an excellent final hardness to thefilm, which is markedly superior to those recorded for conventionalalkyd emulsions, with oil lengths usually of between 40% and 85%.

The invention relates firstly to a polyester resin based on fatty acids,which is short in oil or of zero oil length, modified with rosin and/orderivatives thereof. These resins may be used as organic binders inaqueous dispersion for water-based coatings. More particularly, theresin with a zero oil length (0%) or with an oil length ranging up to 5%may also be used as organic binder for two-pack (2K) non-water-basedcoatings, in particular for “coil” or metal sheet and preferably forgalvanized steel.

Next, the invention relates to an organic binder composition comprisingat least one modified resin as described above and more particularlycomprising, in addition to this modified resin, at least one secondresin different from the first one and selected from polyesters based onfatty acids.

The third subject of the invention concerns an aqueous dispersion ofresin comprising at least one modified resin as defined according to thefirst subject of the invention or at least one organic bindercomposition as defined according to the second subject of the invention.

Another subject of the invention concerns a process for preparing anaqueous dispersion, as defined according to the third subject of theinvention.

The invention also covers a coating composition which comprises at leastone modified resin as defined according to the first subject of theinvention or at least one organic binder composition as definedaccording to the second subject of the invention or at least one aqueousdispersion as defined according to the third subject of the invention.

The invention also relates to the use of the modified resins accordingto the first subject or of the organic binder compositions according tothe second subject or of the aqueous dispersions according to the thirdsubject of the invention, as binder in coating compositions.

Finally, the invention relates to the use of the modified resinsaccording to the first subject with a zero oil length or with an oillength ranging up to 5%, as organic binder in non-water-based coatingsbased on a two-pack reactive system, more particularly for “coil”applications on metal sheets.

DETAILED DESCRIPTION OF CERTAIN EMBODIMENTS OF THE INVENTION

FIG. 1 is a graph depicting the development of hardness on varnishes asa function of time, with siccativation.

FIG. 2 is a graph depicting the development of hardness on varnishes asa function of time, without siccativation.

FIG. 3 depicts differences in blocking resistance between a dispersionprepared according to Example 11 and a reference resin.

Thus, the first subject of the invention relates to a polyester resin,in particular an alkyd resin, which resin:

-   -   is based on at least one fatty acid    -   has a zero oil length (0%) or an oil length between 0 and 35%,        preferably greater than 0 and up to 25%, more preferentially up        to 15%    -   has a weight ratio of oxidizable fatty acids (monoacids)        relative to the overall fatty acids of 0 or more than 0 and        ranging up to 1    -   is based on an acid component comprising, in addition to said        fatty acid, from 30% to 85%, preferably from 35% to 75%, more        preferentially from 40% to 75% and even more preferentially from        45% to 75% by weight, relative to the total weight of said        resin, of rosin and/or rosin derivatives bearing at least one        carboxylic acid function, and more particularly for its        maleinized derivatives (maleinized rosin derivatives), bearing        from 3 to 4 carboxylic functions.

According to a preferred embodiment, the resin of the inventioncomprises less than 5%, preferably less than 3% by weight and morepreferentially no (0%) aromatic compound, for instance of phthalic type(phthalic, isophthalic, trimellitic or terephthalic acid or anhydride),besides the rosin derivatives that may be used. The term “rosinderivatives” means natural derivatives such as dehydroabietic acid.

The resin of the invention is, according to another preferred case,based on an acid component comprising, in addition to said fatty acid,in addition to said rosin and/or in addition to said rosin derivatives,at least one acid compound containing at least one carboxylic acidfunction and having an overall functionality of 2 to 3, the overallfunctionality including the acid function and another possible function,said compound being chosen from: saturated polyacids or ethylenicallyunsaturated polyacids or hydroxy acids. The saturated polyacids have noethylenic unsaturation that is reactive during their use and may verywell be derived from unsaturated polyacids, containing at least onereactive unsaturation, by hydrogenation of these unsaturated polyacids.More particularly, the resin of the invention may be based on an acidcomponent which comprises at least two from among said acid compounds,with at least one chosen from saturated polyacids and another chosenfrom unsaturated polyacids, this being in addition to said fatty acidand said rosin and/or said rosin derivatives. As saturated polyacid thatis suitable for use according to the invention, the choice may be madefrom the acid and/or the anhydride corresponding to: succinic acid offunctionality 2, adipic acid of functionality 2, sebacic acid offunctionality 2, dodecanedioic acid of functionality 2, citric acid offunctionality 3, the C₃₆ fatty acid dimer of functionality 2 to 2.2 orthe C₅₄ fatty acid trimer of functionality 2.5 to 3. As unsaturatedpolyacid that is suitable for use, the choice may be made from theexisting acid and/or anhydride corresponding to: itaconic acid offunctionality 2, maleic or fumaric acid of functionality 2 ortetrahydrophthalic acid (THP) of functionality 2. Among the preferredpolyacids, mention may be made of polyacids comprising at least one C₃₆fatty acid dimer and/or C₅₄ fatty acid trimer. As defined above, saidacid compound, containing at least one carboxylic function and having anoverall functionality of 2 to 3, may also be chosen from hydroxy acidsthat may thus be present in said acid component in addition to the fattyacids and the rosin and derivatives thereof. As preferred hydroxy acidsthat may thus be present, mention may be made of glycolic acid or lacticacid.

A combination of several polyacids and monoacids is often used in orderto optimize the physicochemical properties of the resin, in particularof the alkyd, and more particularly to obtain the desiredhardness/suppleness compromise. The incorporation into the resinsaccording to the invention, in particular into the alkyds, of aromaticacid derivatives such as phthalic derivatives (diacid/anhydride) orbenzoic derivatives (monoacid) is possible, but preferably with acontent of less than 5% by weight and more preferentially with less than3% by weight. Even more preferentially, there is no aromatic derivative(0% aromatics) besides any possible natural rosin derivatives asdescribed above. The presence of a monoacid component such as abietic orpimaric acids, in particular of rosin and/or derivatives thereof, andmore particularly in such a high proportion, constitutes the essentialelement of the invention for enabling the particular propertiesobserved. The rosin content is high and ranges from 30% to 85%,preferably from 35% to 75%, more preferentially from 40% to 75% and evenmore preferentially from 45% to 75%. The fatty acids used, given theirnatural origin, are mixtures comprising saturated fatty acids,unsaturated fatty acids containing non-conjugated unsaturations andunsaturated fatty acids containing conjugated unsaturations. These fattyacids, and also fatty acid dimers and/or trimers synthesized from thesesame natural fatty acids, afford the suppleness and flexibilitynecessary for the binder and the coating obtained which resultstherefrom.

The term “fatty acid” defined in the broadest sense means a C₁₂ to C₅₄carboxylic acid.

The term “oil length”, as used in the present invention, means theweight percentage, relative to the total weight of the resin, of theweight of “fatty monoacids” or of oils or stand oil derivatives (standoil is a product resulting from the reaction at high temperature,250-300° C., of a mixture of oil and fatty acid), this weight percentagebeing expressed as a weight equivalent of triglyceride derivatives(oils) which correspond to the fatty acids, said fatty acids being“oxidizable”. Any calculation or mention of this characteristic in thepresent invention is based on this definition. The term “oxidizablefatty acids” means, according to the present invention, fatty acids orderivatives (oils or stand oils) with an iodine number of greater thanor equal to 80 mg of iodine per g of product. Said monoacids ortriglycerides (oils) may be mixtures of natural origin, comprising up to30% by weight of saturated fatty acids.

Preferably, the proportion of oxidizable (air-reactive) unsaturation inthe resin of the invention is zero (0) or is greater than 0 and rangesup to 0.25 and preferably up to 0.15 mmol of oxidizable double bonds pergram of dry resin (undiluted).

According to a particular possibility, the resin of the invention isbased on an alcohol component comprising at least one polyol offunctionality ranging from 2 to 10 and preferably from 3 to 6. Thepolyols that are suitable for use according to the invention may beselected from: ethylene glycol, polyethylene glycol, preferably with anumber-average molecular mass Mn ranging from 300 to 6000, propyleneglycol (1,2-propanediol), 1,3-propanediol, dipropylene glycol,triethylene glycol, glycerol, diglycerol, trimethylolpropane ortrimethylolethane, pentaerythritol, dipentaerythritol, sorbitol,mannitol, methyl glucoside, polyglycerol, in particular glycerololigomers, such as Polyglycerol-3 (glycerol trimer) and decaglyceroland, preferably, glycerol oligomers and mixtures thereof, such asPolyglycerol-3, which Polyglycerol-3 is a mixture of glycerol oligomers(glycerol oligomerized in the presence of oligomers containing 30% to55% by weight of glycerol trimer constituting the predominant oligomer),this product being sold by Solvay. The polyol that is most preferred ispolyglycerol-3 which is oligomerized and has a molecular mass markedlygreater than that of glycerol, with a functionality ranging from 5 to 6.By virtue of its higher molecular mass and of its high functionality,this polyol makes it possible more readily to increase the finalmolecular mass of the resin, in particular of the alkyd resin, while atthe same time ensuring a narrower molecular distribution.

The preferred resin of the invention has an acid number of less than 8and a number-average molecular mass Mn ranging from 1000 to 10 000g/mol, measured by GPC in THF and expressed as polystyrene equivalents.

The Tg of the resin of the invention measured by DSC, after two passagesat a temperature sweep speed of 10° C./min, may range from −40 to 50° C.and preferably from −20 to 35° C.

More particularly, according to a first version, the resin has an oillength that is between 0 and 35%, and is preferably greater than 0 andranges up to 25% and more preferentially up to 15%, with presence of atleast one oxidizable fatty acid (monoacid). This means that the resincomprises an air-oxidizable structure. According to a more particularcase of this oxidizable resin version, the content of oxidizableunsaturation in said resin is greater than 0 and may range up to 0.25and preferably up to 0.15 mmol of oxidizable double bonds per gram ofdry resin. In such a case (resin of oxidizable structure), said fattyacid is selected from fatty monoacids of plant or animal originpreferably of C₁₆ to C_(24,) with a mean iodine number ranging from 100to 200.

According to the given definition of the invention, the fatty acid maybe an oxidizable fatty acid (fatty monoacid) or a non-oxidizable fattyacid, in particular a polyacid such as fatty acid oligomers and inparticular C₃₆ and C₅₄ fatty acid dimers and/or trimers, respectively.Said fatty acid may be oxidizable and selected from fatty acids ofsoybean oil, sunflower oil, tall oil (TOPA), castor oil, dehydratedcastor oil, linseed oil or rapeseed oil, said fatty acids being used assuch or in the form of corresponding oils (triglyceride esters) of fattyacids or in the form of corresponding stand oils of fatty acid oils.Said stand oils, which are well known to those skilled in the art, arein fact derivatives of fatty acid oils obtained at high temperature bystandolization of these oils. These cases of fatty acids or of fattyacid oils have oxidizable unsaturations as defined above according tothe iodine number characteristic of greater than or equal to 80 mg ofiodine per gram of produced acid or oil or stand oil of fatty acid oil.

According to a preferred version of the resin of the invention, it isbased on a polyacid comprising at least one C₃₆ fatty acid dimer and/orC₅₄ fatty acid trimer and based on a polyol comprising at least oneglycerol and/or pentaerythritol and/or dipentaerythritol oligomer,preferably a mixture of glycerol oligomers comprising the glyceroltrimer, more particularly polyglycerol-3.

According to a more particular version, the polyester resin of theinvention is an alkyd resin, with an oil content (oil length) of greaterthan 0%, preferably ranging up to 25% and more preferentially up to 15%.

Another category of resin according to the invention has a zero oillength or oil content (0%) and is commonly referred to as being“oil-free”, with said fatty acid being selected from non-oxidizablefatty acids and thus with a corresponding content of oxidizableunsaturation that is 0 mmol per gram of dry resin. In this case, saidfatty acid is preferably selected from saturated fatty acids (includingfatty acids that are initially oxidizable, which have been hydrogenatedand consequently become non-oxidizable) or from fatty acid oligomers,preferably C₃₆ dimers (including hydrogenated dimers) and/or C₅₄ trimers(including hydrogenated trimers). Preferably, such a resin (0% oil) isbased on an alcohol component comprising as polyol a glycerol oligomer,preferably a mixture of glycerol oligomers, and more preferentiallypolyglycerol-3, and, as fatty acid, a C₃₆ fatty acid dimer and/or a C₅₄fatty acid trimer (hydrogenated or non-hydrogenated). A resin withcomparable behavior, in particular for applications in a two-packcoating system, is also a resin with an oil content ranging up to 5%,which, in addition to said fatty acid selected from the non-oxidizablefatty acids as defined above, comprises (in addition) minor weightproportions of an oxidizable fatty acid leading to said oil proportionranging up to 5%. Said oxidizable fatty acid, which is minor in thelatter case, may be present as residual acid with the rosin used: forexample, “tall oil” rosin comprises small proportions (about 4%) of talloil fatty acid, which is oxidizable. Thus, as in this particular case,said oxidizable acid may also be present or added in such minorproportions to arrive at an oil length that may be up to 25%.

The preparation of said resin according to the invention, in particularthe alkyd, is performed by polycondensation reaction under an inertatmosphere at standard temperatures of between 180° C. and 300° C.,preferably between 250° C. and 270° C., and more preferentially withapplication of a vacuum (reduced pressure) of moderate level rangingfrom 50 to 250 mmHg, at the end of the polycondensation in order toreduce the reaction times. It is possible, in order to prevent and/orfurther reduce the coloration and oxidation of the rosin during thesynthesis, to use additives, in particular antioxidants, as employed inthe preparation of rosin esters used in particular for adhesives: phenolsulfites, paraformaldehyde, hypophosphorous acid, trialkyl or triphenylphosphites. A more exhaustive list of additives that may be used forthis purpose is described in U.S. Pat. No.4,744,925, column 2, lines50-62, which list is incorporated herein by reference.

The second subject of the invention is thus an organic bindercomposition which comprises at least one resin as defined aboveaccording to the invention.

According to a more preferred case, this composition comprises at leasttwo resins and, more precisely, in addition to the first resin asdefined according to the invention above, it comprises at least onesecond resin different from the first, and with this second resin beingselected from resins of polyesters based on fatty acids, preferably frommodified alkyd resins. Thus, preferably, said polyesters based on fattyacids are chemically modified alkyds chosen from: silicone alkyds,urethane alkyds, alkyd-acrylic hybrids. These binder compositions may beused as such or in the preparation of the aqueous dispersions of resinsof the invention, for water-based coatings.

According to a particular variant of this organic binder composition,which is well suited to non-water-based or solvent-based coatings andmore particularly for two-pack (2K) reactive systems, even moreparticularly for “coil” coatings on metal sheets, said first resin is aresin according to the invention and has a zero oil length (0%) or anoil length ranging up to 5%.

The third subject of the invention is an aqueous dispersion of resinwhich comprises at least one resin or at least one binder composition asdefined above according to the present invention. According to aparticular preferred variant of this aqueous dispersion according to theinvention, it comprises, in addition to said resin or said bindercomposition, both as defined according to the invention described above,at least one surfactant selected from: at least one anionic surfactantand at least one nonionic surfactant or at least one surfactant of mixedstructure and with an overall weight content relative to said resinranging from 2% to 15% and preferably from 5% to 10%. According to thepresent invention, a surfactant of mixed structure is a surfactant whichcomprises both a nonionic structure, such as a polyoxyalkylene segment(more particularly oxyethylene and/or oxypropylene units) and an anionicstructure (for instance a sulfonate or sulfate or phosphate orphosphinate group) on the same molecule or molecular chain. Examples ofsuch surfactants that may be mentioned include sulfonate or sulfate orphosphate phosphinate esters of polyether alcohols or of alkoxylatedfatty alcohols, with nonionic structures (polyether) and anionicstructures (sulfate, sulfonate or phosphate or phosphinate), combined onthe same molecule.

The dispersion according to the invention may have a solids contentranging from 30% to 70% and preferably from 40% to 60% and a meanparticle size ranging from 100 to 500 nm. The preferred dispersionaccording to the invention is free of any organic solvent, this meaning,according to the present invention, a corresponding content of volatileorganic compounds (VOC) in said dispersion of less than 1000 ppm,preferably less than 500 ppm and more preferentially less than 100 ppm.

Even more particularly, the aqueous dispersion of resin according to thepresent invention is a mixture of, or comprises as a mixture, a firstaqueous dispersion of resin as defined according to the invention asdescribed above and at least one second dispersion of resin, whichsecond dispersion is different from the first dispersion, this seconddispersion of resin being selected from dispersions of alkyds, which areoptionally modified, or acrylic, including styrene-acrylic, dispersions(or emulsions), or dispersions of other polymers and in particulardispersions of saturated or unsaturated polyesters, or polyurethanes.According to this particular case of aqueous dispersion, the weightcontent of said first dispersion ranges from 50% to 99.5%. Said modifiedalkyd dispersions that may be suitable for said second dispersion,according to this particular case, are chosen from alkyd dispersionsmodified with acrylic, styrene, styrene-acrylic, vinyl, silicone orurethane. Said second dispersion is also selected so as to be compatiblewith the first aqueous dispersion as defined according to thisparticular dispersion case and, more particularly, it is based on aresin or a polymer that is compatible with the resin of the presentinvention, which resin has as specificity a greatly reduced or zero oillength.

A fourth subject of the invention concerns a process for preparing saidaqueous dispersion, which process comprises a step of emulsification ata temperature of from 30 to 90° C. and preferably from 50 to 85° C. ofat least one resin and/or of at least one organic binder composition,the resin and the binder composition as defined above according to theinvention, by phase inversion in a reactor stirred via a dual-flowstirring system.

In point of fact, the resins, after the final polycondensation phase,are cooled to 120-180° C. and are then transferred into an emulsifier inorder to be dispersed therein in water in the presence of surfactants.The emulsion is preferably obtained via the phase inversion techniqueusing a reactor stirred via a dual-flow system at a temperature ofbetween 30° C. and 90° C. and preferably at 50-85° C. The directemulsification technique is incompatible with this type of resin. Thetemperature imposed during the phase inversion is adjusted as a functionof the intrinsic viscosity at elevated temperature of the alkyd orpolyester resin. The resin is emulsified, at neutral or slightlyalkaline pH, via more or less partial neutralization of the residualcarboxylic functions, according to a standard process combining asurfactant or, preferably, a mixture of ionic (anionic) surfactant andof nonionic surfactant. For these two types of process, at least onesurfactant is used. This surfactant is selected from ionic, preferablyanionic, and/or nonionic and/or hybrid surfactants of mixed structure(comprising in the same molecule a nonionic structure such as anethoxylated and/or propoxylated structure and an anionic structure). Thepresence of surfactants improves the stability of the dispersion, thuspreventing sedimentation and/or coalescence during the hot formingprocess and during the storage/use of the product. A selection criterionfor the nonionic surfactants used is the HLB index(hydrophilic-lipophilic balance) representing the ratio of hydrophilicand hydrophobic characters in the surfactant. Preferably, a combinationof a nonionic surfactant and of an anionic surfactant is preferred toobtain stable dispersions with a small particle size, preferably lessthan 300 nm. Among the anionic surfactants that are suitable for thisinvention, mention may be made of sodium, lithium, potassium, ammoniumor magnesium salts, alkyl ether sulfates with alkyl ranging from C₈ toC₁₈ or C₁₂ alkyl benzene sulfates or alkyl sulfates, alkyl phosphate ordialkyl sulfosuccinate esters or even soaps obtained from thecorresponding fatty acids. The anionic surfactants are preferably usedwith at least one nonionic surfactant. Examples of mixed surfactants(nonionic+anionic mixed structure) include alkoxylated alkyl phenolsulfonates or phosphonates. The nonionic surfactants may be used alone,but, preferably, they are in combination with an anionic surfactant. Aspreferred examples of suitable nonionic surfactants, mention may be madeof: ethoxylated C₁₂-C₁₈ fatty alcohols (6 to 50 OE), ethoxylated iso C₁₀fatty alcohols (6 to 50 OE), ethoxylated mono-branched C₁₀-C₁₈ fattyalcohols (6 to 50 OE), sorbitol fatty esters, ethoxylated sorbitolesters (5-50 OE), alkyl polyglucosides, glucamides, glycerol, diglycerolor polyglycerol fatty esters, ethoxylated fatty acids (7-100 OE),ethoxylated castor oil (hydrogenated or non-hydrogenated) (30-40 OE),glycol or polyethylene glycol fatty acids, nonionic polymers and otherblock copolymers, for instance poly(propylene glycol)-poly(ethyleneglycol) block copolymer. The preferred aqueous dispersion comprises atleast one nonionic surfactant optionally combined with at least oneanionic surfactant in an overall (nonionic plus anionic) weight contentrelative to the alkyd or polyester resin of from 2% to 15%, preferablyfrom 5% to 10%, and with a preferred ionic to nonionic weight ratioranging from 25/75 to 50/50 in the case of a nonionic and anioniccombination. The pH of the medium is preferably adjusted as a functionof the acidity of the resin. This is why a basic aqueous solution, offrom 1% to 50% and preferably from 10% to 20% by weight of base, isinitially introduced after the addition of the surfactants, at theemulsification temperature (ef. table 4). To this end, basic (alkaline)aqueous solutions are used starting with LiOH, NaOH, KOH, aqueousammonia or amines, preferably tertiary or hindered amines that are moreor less hydrophilic, such as diethanolamine, triethanolamine,aminomethylpropane or triethylamine.

The aqueous dispersion of the resin may also be obtained byself-emulsification of the resin without surfactant, for a resin with anacid number of at least 40 mg KOH/g, after at least partialneutralization of the carboxylic functions of the resin. However, in thecontext of the present invention, it is preferable for the acid numberto be <8 in order to have the best water resistance for the resultingfinal coating.

The aqueous dispersion according to the invention is preferably free ofany protective colloid.

The dry extracts or solids contents of said dispersions of the inventionrange from 30% to 70%, preferably from 40% to 60% and morepreferentially from 40% to 55%.

Another subject of the invention relates to a coating composition whichcomprises as binder at least one resin or at least one bindercomposition or at least one aqueous dispersion, with said resin orbinder composition or aqueous dispersion being as defined aboveaccording to the invention. According to a more particular and preferredcase, said composition is a water-based coating composition. Saidcoating is preferably selected from decorative or industrial coatings,and in particular, for industrial coatings, chosen from anticorrosioncoatings, and preferably from water-based coatings for adhesives,paints, surface coatings, primers and varnishes. The preferred coatingis selected from decorative or industrial water-based varnishes orpaints. These water-based coating compositions and in particular paintsand varnishes have the additional advantage of drying withoutmandatorily supplying (or at a reduced level) a siccativating agent.

The coating composition based on aqueous dispersions may also comprise asiccativating agent, which may be present in a reduced or zero content(normal), and in this case said resin used as binder preferably has anoil length ranging up to 25% and preferably from 15% to 25%. Given theirappropriate molecular masses and oil length, said resins in particularwith an oil content ranging from 15% to 25%, under the effect of asiccativating agent such as cobalt, allow, in addition to high hardnessand great resistance to yellowing, excellent blocking resistance, withno point of attachment or of peeling observed in a test, after dryingfor 24 hours at room temperature and 24 hours of contact. Such blockingresistance performance is expected only for certain acrylic dispersions,but is entirely exceptional for polyester dispersions, in particularalkyd dispersions, as described in the present invention.

Moreover, the presence of hydroxyl functions in the resins definedaccording to the invention makes it possible to produce, forapplications termed industrial, crosslinks by means of a secondcomponent (two-pack system known as 2K) such as isocyanates (blocked ornon-blocked) or melamines to form films with a higher molecular weightleading to superior mechanical or chemical properties: chemicalresistance and mechanical strength such as increased longevity anddurability.

The coating composition according to the present invention also covers acoating composition which comprises as binder at least one resin asdefined above according to the invention and having a zero oil length(0%) or a resin having an oil length ranging up to 5% as defined aboveor at least one binder composition based on such a resin (zero oillength or oil length ranging up to 5% as defined above). This particularcoating composition more particularly concerns an anticorrosionprotective coating of great chemical resistance for coil applications.More particularly, such a coating composition may be used in a two-pack(2K) reactive system.

A penultimate subject of the invention relates to the use of at leastone resin or of at least one binder composition or of at least oneaqueous dispersion, as defined above according to the invention, asbinders in coatings. More particularly, this use relates to decorativeor industrial water-based coatings selected from adhesives, paints,surface coatings, primers or varnishes. These coatings are suitable forsubstrates selected from: wood, metals, plaster, concrete, composites orplastics, plastics such as silicone, polyethylene, PVC, polycarbonate,polypropylene or polystyrene.

A more particular use concerns resin with a zero oil length or with anoil length ranging up to 5%, as defined above according to the inventionor the corresponding binder composition or aqueous dispersion(comprising said resin), this use being as a binder for two-pack (2K)reactive systems in coil coatings, for marine applications or asanticorrosion for protecting metals (metal surfaces).

Moreover, the high hydrophobicity and the excellent adhesion, which arequalities afforded by said resins in aqueous dispersion according to thepresent invention, make it a preferred binder that may be used equallywell in coatings in aqueous and non-aqueous medium for preventing thecorrosion of metal surfaces. Among the other substrates selected, woodmay also be found, it being noted that the hydrophobic nature and thepresence of “rosin” units derived from the wood, offer excellentproperties of adhesion to wood. Surprisingly, we have also found, bychance, that these binders also had high properties of adhesion toplastics such as silicone, polyethylene, ABS, polycarbonate or PVC, orto plaster, ceramic, brick or composite materials. The coatingcompositions formulated with at least one aqueous dispersion of saidresin may contain a significantly reduced or even zero content of atleast one siccativating agent. Preferably, these compositions may befree of siccativating agents and in particular free of cobalt assiccativating agent. Similarly, by virtue of its high potential forphysical drying, slightly larger coating thicknesses would be allowedfor equivalent drying times, thus increasing the productivity and alsoimproving the conditions and working intervals (shortened interval) forthe handling and use of coated pieces, after coating.

The final subject of this invention relates to substrates coated with atleast one (substrate) coating, obtained from at least one resin or fromat least one binder composition or from at least one aqueous dispersionof resin or from at least one coating composition derived from saidresin, as defined above according to the present invention. In certainapplications with a high concentration of fillers and in a two-packsystem, supplying a siccativating agent based on cobalt, manganese,lead, vanadium, calcium, barium, strontium, cerium, zinc and iron isunnecessary. Already, given the physical drying performance demonstratedby the compositions based on resin of reduced oil length, in particularfrom 0 to 15%, the presence of siccativating agent is in no wayessential with such a coating composition.

EXPERIMENTAL SECTION

By way of illustration of the invention, the following examplesdescribe, without any limitation on the claimed subjects, the synthesisof said resins for binders, in particular water-based, and theperformance of the dispersions and of the coatings thus obtained. Anillustration of the performance in a two-pack (2K) system is alsopresented at the end of the experimental section.

1) Raw Materials Used (See Table 1 Below)

TABLE 1 Raw materials used for the preparation of the tested resins Acidor Commercial Iodine hydroxyl name number number or product Chemical (mg(mg type Supplier name Function I₂/g) KOH/g) Nouracid ® Oleon SoybeanFatty 120-150  195-205 SZ35 fatty acid acid SYLFAT ® Arizona Tall oilFatty 155  194 2 fatty acid acid   Pripol ® Croda Fatty acid Polyacid / 195-205 dimer Pripol ® 1017 Croda Mixture of Polyacid /  195-210 fattyacid dimers and trimers (75/25) Itaconic acid Acros Itaconic acidPolyacid /  860 Organics   Rosin of TER- Pine oil rosin, Rosin / 165-175 Chinese HELL & with a content Pinus CO of resinous massonianaGMBH acids type ~90% FOR85 Forchem Tall oil rosin, Rosin /  165-175resinous acids: >85% Hydrogral ® DRT Hydrogenated Rosin /  163 rosinResinous acids: ~89% Succinic acid Aldrich Succinic acid Polyacid /  950Sebacic acid Aldrich Sebacic acid Polyacid /  550 Polyglycerol- SolvayPolygrycerol Polyol / 1000- 3 (mixture of 1200 oligomers, centered on35-55% trimers) Pentaerythritol Perstorp Pentaerythritol Polyol / 1645Glycerol Cargill 1,2,3- Polyol / 1828 Propanetriol AOX-R Allad- 4-4′-Anti- — — chem Thiobis(3- oxidant methyl-6- tert- butylphenol) (CAS96-69-5) Zephrym ® CRODA Ammonium Anionic 3300 dodecyl- surfac- benzene-tant sulfonate Atlas ® CRODA Propylene Non- G5000 oxide/ethylene ionicoxide block surfac- copolymer tant Synaqua ® Cray Short-oil Refer- 4804*Valley (37%) alkyd ence resin as a resin dispersion in water (solidscontent: 50%) Synolac ® Cray Polyester resin 9605 S 65 Valley forgeneral Refer- “coil” appli- ence cation resin BORCHI ® OMG- Ironcomplex Siccati- OXY-COAT BOR- dissolved in vating CHERS propylene agentglycol DURHAM ® ROCK- Cobalt Siccati- COBALT WOOD complex vatinng 10WMPIG- dissolved in a agent MENTS dearomatized hydrocarbon- based solventACTICIDE ® THOR Aqueous Biocide MBS CHEMIE solution of methylisothia-zoline (MIT) and of benzisothiazo- linone (BIT) DISPER- BYK Block copol-Disper- BYK ® CHEMIE ymers con- sant MBS taining groups with highaffinity for pigments BYK ® 022 BYK Polysiloxane Anti- CHEMIE baseantifoam foam TIONA ® CRISTAL Titanium Pigment 595 GLOBAL dioxide AQUA-AQUA- Hydro- Thick- FLOW ® LON- phobically ener NMS 450 HERCU- modifiedLES polyacetal polyether AQUA- AQUA- Modified Thick- FLOW ® LON-polyacetal ener NHS 300 HERCU- polyether LES *Symbolized as SA4804 inFIGS. 1 and 2

2) Preparation of the Starting Resins

13 resins were prepared according to the corresponding proceduresdescribed below in Examples 1 to 13.

EXAMPLE 1

185.2 g of Pripol® 1009, 1453.3 g of pine oil rosin, 6 g of AOX-R(phenol sulfite) and 185.2 g of polyglycerol-3 are placed in a stirred,temperature-regulated 5-liter reactor, under a nitrogen atmosphere. Themixture is heated to 250-270° C. and the water of condensation isremoved until an acid number of 6 mg KOH/g is obtained.

EXAMPLE 2

The same procedure as for Example 1 is used with the following productsand amounts: 592.0 g of Pripol® 1009, 1034.0 g of pine oil rosin, 6 g ofAOX-R (phenol sulfite) and 374.0 g of polyglycerol-3. The water ofcondensation is removed until an acid number of 4 mg KOH/g is obtained.

EXAMPLE 3

The same procedure as for Example 1 is used, but with the followingproducts and amounts: 6.5 g of soybean fatty acid Nouracid® SZ35, 71.4 gof pine oil rosin and 22.0 g of polyglycerol-3. The water ofcondensation is removed until an acid number of 4 mg KOH/g is obtained.

EXAMPLE 4

85.0 g of tall oil fatty acid, 837.0 g of tall oil rosin (For 85), 84.0g of succinic acid and 264.9 g of polyglycerol-3 are placed in astirred, temperature-regulated 2-liter reactor, under a nitrogenatmosphere. The mixture is heated to 250-270° C. and the water ofcondensation is removed until an acid number of less than 6 mg KOH/g isobtained.

EXAMPLE 5

The same procedure as for Example 4 is used, but starting with thefollowing amounts: 9.3 g of soybean fatty acid, 64.2 g of pine oilrosin, 5.2 g of succinic acid and 22.0 g of polyglycerol-3. The mixtureis heated to 250-270° C. and the water of condensation is removed untilan acid number of less than 4 mg KOH/g is obtained.

EXAMPLE 6

9.5 g of soybean fatty acid, 65.6 g of pine oil rosin and 21.2 g ofpolyglycerol-3 are placed in a stirred, temperature-regulated 0.25 literreactor, under a nitrogen atmosphere. The mixture is heated to 250-270°C. and the water of condensation is removed until an acid number of lessthan 2-3 mg KOH/g is obtained. Next, 3.25 g of itaconic acid are addedat 150° C. and the mixture is heated at 180° C. until a final acidnumber of 8 mg KOH/g is obtained.

EXAMPLE 7

139.6 g of soybean fatty acid Nouracid® SZ35, 868.2 g of pine oil rosin,83.6 g of succinic acid, 68.1 g of sebacic acid and 340.5 g ofpolyglycerol-3 are placed in a stirred reactor as in Example 4. Themixture is heated to 250-270° C. and the water of condensation isremoved until an acid number of less than 6 mg KOH/g is obtained.

EXAMPLE 8

116.5 g of soybean fatty acid Nouracid® SZ35, 801.5 g of tall oil rosin,67.6 g of succinic acid and 264.9 g of polyglycerol-3 are placed in astirred reactor as in Example 4. The mixture is heated to 250-270° C.and the water of condensation is removed until an acid number of lessthan 7 mg KOH/g is obtained. 16.5 g of succinic acid are then added andthe condensation is continued until an acid number of 5.5 mg KOH/g isobtained.

EXAMPLE 9

180.0 g of SYLFAT® 2 (tall oil fatty acid), 770.0 g of pine oil rosin,69.0 g of succinic acid and 273.9 g of polyglycerol-3 are placed in astirred reactor as in Example 4. The mixture is heated to 250-270° C.and the water of condensation is removed until an acid number of lessthan 7 mg KOH/g is obtained. Next, 22.8 g of succinic acid are added andthe condensation is continued until an acid number of 4 mg KOH/g isobtained.

EXAMPLE 10

220.0 g of SYLFAT® 2 (tall oil fatty acid), 664.0 g of pine oil rosin,73.6 g of succinic acid, 255.9 g of Pripol® 1017 (75/25 fatty aciddimer/trimer mixture) and 255.9 g of polyglycerol-3 are placed in astirred reactor as in Example 4. The mixture is heated to 250-270° C.and the water of condensation is removed until an acid number of lessthan 5 mg KOH/g is obtained.

EXAMPLE 11

224.0 g of SYLFAT® 2 (tall oil fatty acid), 630.0 g of pine oil rosin,35.0 g of sebacic acid, 69.0 g of succinic acid and 273.9 g ofpolyglycerol-3 are placed in a stirred reactor as in Example 4. Themixture is heated to 250-270° C. and the water of condensation isremoved until an acid number of less than 7 mg KOH/g is obtained. Next,17.8 g of succinic acid are added and the condensation is continueduntil an acid number of 3 mg KOH/g is obtained.

EXAMPLE 12

270.0 g of SYLFAT® 2 (tall oil fatty acid), 520.0 g of pine oil rosin,47.5 g of sebacic acid, 69.0 g of succinic acid and 273.9 g ofpolyglycerol-3 are placed in a stirred reactor as in Example 4. Themixture is heated to 250-270° C. and the water of condensation isremoved until an acid number of less than 7 mg KOH/g. Next, 17.8 g ofsuccinic acid are added and the condensation is continued until an acidnumber of 3-4 mg KOH/g is obtained.

EXAMPLE 13

310 g of SYLFAT® 2 (tall oil fatty acid), 475 g of pine oil rosin, 69.0g of succinic acid, 78.1 g of sebacic acid and 273.9 g of polyglycerol-3are placed in a stirred reactor as in Example 4. The mixture is heatedto 250-270° C. and the water of condensation is removed until an acidnumber of 3 mg KOH/g is obtained.

The compositions of the 13 resins prepared according to Examples 1-13are presented in Table 2 and the corresponding physicochemicalcharacteristics are given in Table 3 below.

Additional Examples 14 to 17 of Polyester Resins for “Coil” Two-Pack UseEXAMPLE 14

444.0 g of Pripol® 1009, 775.5 g of hydrogenated rosin (Hydrogral®), 6.0g of AOX-R (phenol sulfite) and 280.5 g of polyglycerol-3 are placed ina stirred, temperature-regulated 2-liter reactor, under a nitrogenatmosphere. The mixture is heated to 250-270° C. and the water ofcondensation is gradually removed until an acid number of 6 mg KOH/g isobtained. The resin is then cooled and dissolved in a mixture ofSolvarex® 9 (from TOTAL)/butyl glycol (80/20, m/m) until a final solidscontent of 70% is obtained. The viscosity of the solution obtained isbetween 2000 and 3000 mPa·s.

EXAMPLE 15

555.0 g of Pripol® 1009, 753.2 g of hydrogenated rosin (Hydrogral®), 6.0g of AOX-R (phenol sulfite) and 191.9 g of pentaerythritol are placed ina stirred, temperature-regulated 2-liter reactor, under a nitrogenatmosphere. The mixture is heated to 250-270° C. The water ofcondensation is gradually removed until an acid number of between 6 and10 mg KOH/g is obtained for a viscosity of between 6500 and 7500 mPa·sobtained by dilution with a mixture of Solvarex® 9 (TOTAL)/butyl glycol(80/20, m/m) as described in Example 14.

EXAMPLE 16

468.8 g of Pripol® 1017, 754.6 g of pine oil rosin, 6.0 g of AOX-R.(phenol sulfite), 80.0 g of succinic acid and 196.6 g of glycerol areplaced in a stirred, temperature-regulated 2-liter reactor, under anitrogen atmosphere. The mixture is heated to 250-270° C. The water ofcondensation is gradually removed until an acid number of between 2 and6 mg KOH/g is obtained for a viscosity of between 2000 and 3000 mPa·sobtained by dilution with a mixture of Solvarex® 9 (TOTAL)/butyl glycol(80/20, m/m) as described in Example 14.

EXAMPLE 17

411.8 g of Pripol® 1009, 807.0 g of rosin FOR85, 4.5 g of AOX-R (phenolsulfite) and 280.4 g of polyglycerol-3 are placed in a stirred,temperature-regulated 2-liter reactor, under a nitrogen atmosphere. Themixture is heated to 250-270° C. The water of condensation is graduallyremoved until an acid number of between 2 and 6 mg KOH/g is obtained fora viscosity of between 2500 and 3000 mPa·s obtained by dilution with amixture of Solvarex® 9 (TOTAL)/butyl glycol (80/20, m/m) as described inExample 14.

The four examples, 14 to 17, correspond to four polyester resins thatare variants of the polyester described in Example 2 with a zero oillength or with an oil length of less than 5% as defined above accordingto the invention, with a rosin content that is in the region of 50% to52%, polyesters prepared specifically for the needs of more particularapplications of coil two-pack type.

The compositions of the resins of the four examples 14 to 17 arepresented in Table 2a and the physicochemical characteristics in Table3a.

TABLE 2 Chemical composition (weight %) of the resins of Examples 1-13Example 1 2 3 4 5 6 7 8 9 10 11 12 13 Rosin* 72.6 51.7 71.4 65.8 64.265.6 57.9 63.3 58.5 43.3 50.4 43.4 39.4 Polyglycerol-3 18.1 18.7 22.120.8 21.2 21.7 22.7 20.9 20.8 20.9 21.9 22.9 22.7 Soybean fatty acid(Nouracid ® SZ35) 6.5 6.7 9.3 9.5 9.3 9.2 Tall oil fatty acid (Sylfat ®2) + residual 13.7 14.3 17.9 22.5 25.7 tall oil fatty acid present inrosin** Pripol ® 1009 9.3 29.6 Pripol ® 1017 16.7 Succinic acid 6.6 5.25.6 6.6 7.0 4.8 6.9 7.2 5.7 Sebacic acid 4.5 2.9 4.0 6.5 Itaconic acid3.2 Oil length (weight % vs resin) 0 0 7 10 10 10.5 10 13 15 16 20 25 29*The mass content indicated in the table corresponds only to theproportion of rosin: any residual fatty acids that may be present in theinitial mixture are not counted. **This comment concerns only theexamples in which tall oil rosin was used (this starting materialcontains about 4% tall oil fatty acid).

TABLE 3 Physicochemical properties of the resins for air dryingapplication via an aqueous formulation according to Examples 1 to 13Example 1 2 3 4 5 6 7 Rosin* weight % vs resin 72.7 51.8 71.4 65.8 64.265.6 57.9 Oil length (%) (oxidizable) 0 0 7 10 10 10.5 10 Overall fattyacid content 9.3 29.6 6.5 9.2 9.3 9.5 9.3 (oxidizable or non-oxidizable)Oxidizable fatty acid content/ 0 0 1 1 1 1 1 overall fatty acid contentRatio: rosin equivalent/fatty 6.4 1.4 9.1 8.1 5.7 5.7 5.1 acidequivalent (oxidizable or non-oxidizable) Oxidizable C═C (mol/kg) 0 00.035 0.058 0.052 0.051 0.051 Measured Mn (SEC or GPC) 1350 2550 11002000 1750 1700 2550 Tg resin (° C.) 33 10 29 21 18 21 19 Gardner color6.5 5.0 9.0 6.0 6.6 8.0 8.2 Acid number 6.2 4.0 4.0 5.6 2.1 7.0 2.4Example 8 9 10 11 12 13 Rosin* weight % vs resin 63.3 58.5 43.3 50.443.4 39.4 Oil length (%) (oxidizable) 13 15 16 20 25 29 Overall fattyacid content 11.7 13.7 31.1 17.9 22.5 25.7 (oxidizable ornon-oxidizable) Oxidizable fatty acid content/ 1 1 0.46 1 1 1 overallfatty acid content Ratio: rosin equivalent/fatty 5.7 3.5 1.1 2.3 1.6 1.3acid equivalent (oxidizable or non-oxidizable) Oxidizable C═C (mol/kg)0.058 0.089 0.106 0.117 0.147 0.168 Measured Mn (SEC or GPC) 2000 22503250 3000 3250 3350 Tg resin (° C.) 11 13 −7 3 −13 −20 Gardner color 5.16.0 8.0 8.5 7.0 8.0 Acid number 5.5 4.2 5.0 3.0 3.5 3.0 *The masscontent indicated in the table corresponds only to the proportion ofrosin: any residual fatty acids that may be present in the initialmixture are not counted

TABLE 2a Compositions of the resins of Examples 14-17 Examples 14 15 1617 Rosin* 51.7 50.2 50.3 51.7 Polyglycero1-3 18.7 18.7 Pentaerythritol12.8 Glycerol 13.2 Residual tall oil fatty acid 2.1 present in rosin**Pripol ® 1009 29.6 37.0 27.5 Pripol ® 1017 31.2 Succinic acid 5.3 Oillength (weight % vs resin) 0 0 0 2.4 *The mass content indicated in thetable corresponds only to the proportion of rosin: any residual fattyacids that may be present in the initial mixture are not counted. **Thiscomment concerns only the examples in which tall oil rosin was used(this starting material contains about 4% tall oil fatty acid).

TABLE 3a physicochemical characteristics of the resins according toExamples 14 to 17 Example 14 15 16 17 Rosin* weight % vs resin 51.7 50.250.3 51.7 Oil length (%) (oxidizable) 0 0 0 0 Overall fatty acid content29.6 37.0 31.2 29.6 oxidizable or non-oxidizable) Oxidizable fatty acidcontent/ 0 0 0 0.07 overall fatty acid content Ratio: rosinequivalent/fatty 1.4 1.1 1.3 1.4 acid equivalent (oxidizable ornon-oxidizable) Oxidizable C═C 0 0 0 0.004 (mol/kg) Measured Mn (SEC orGPC) 2550 3150 2400 2500 Tg resin (°C.) 8 2 7.5 9 Gardner color 6.1 7.57.8 5.2 Acid number 5.7 7.4 2.9 3.5 *The mass content indicated in thetable corresponds only to the proportion of rosin: any residual fattyacids that may be present in the initial mixture are not counted.

3) Preparation of the Tested Aqueous Dispersions, Corresponding to theResins Prepared According to Examples 1 to 13

The resins prepared according to the conditions described in Examples 1to 13 (see point 2 above) are dispersed in water according to the samegeneral procedure and as described below, with the sole exception of thedispersion temperature, which may vary as a function of the initialviscosity of the resin to be dispersed.

435.0 g of resin, as prepared according to Examples 1-13 described above(see point 2), melted beforehand at between 60 and 100° C., as a mixturewith the following surfactants, 18.5 g of ATLAS® G5000 and 8.5 g ofZEPHRYM® 3300B (both supplied by Croda) are placed in a 1.5 literreactor equipped with an efficient stirring system (mechanical) and arestirred for 45 minutes at a temperature of between 60° C. and 80° C.(see the values indicated in Table 4 below). If need be, the acid numberof the resins is adjusted before neutralization by addition of soybeanfatty acid, Nouracid® SZ35, in order to obtain a minimum acid number of4-5 mg KOH/g. A neutralizing solution of 10% LiOH in water is thengradually added at the same temperature. It is important to note thatthis addition-neutralization is accompanied by a large increase in theviscosity of the medium, which is why it is essential to employefficient mechanical stirring that is capable of operating in extremelyviscous media. Finally, water is introduced at between 60-67° C. until asolids content of 40-55% is obtained. The solids content and the pH areadjusted if necessary. The final emulsion is then cooled and dischargedin order subsequently to be characterized and evaluated.

The results of the characterization of the emulsions are collated inTable 4 below.

TABLE 4 Characteristics of the aqueous dispersions of the resins ofExamples 1 to 13 Example vs resin 1 2 3 4 5 6 7 8 9 10 11 12 13Emulsification 70° C. 80° C. 67° C. 70° C. 70° C. 70° C. 70° C. 70° C.70° C. 70° C. 70° C. 80° C. 80° C. temperature Particle size (nm) 232153 159 301 332 140 332 274 263 236 244 315 285 Particle polydispersity0.06 0.02 0.07 0.17 0.10 0.16 0.18 0.04 0.00 0.03 0.05 0.00 0.00 pH 8.98.5 9.5 8.0 8.8 9.4 8.9 7.4 9.1 8.7 8.5 8.3 8.2 % solids content 50.046.3 39.0 50.1 49.9 41.5 50.2 50.4 50.3 50.4 50.7 48.9 50.8

4) Preparation of Varnish Formulations Based on the Dispersions Preparedfrom Resins According to Examples 1 to 13

The general procedure for preparing these varnish formulations is asfollows: 150 g of aqueous binder (aqueous dispersion) as preparedaccording to the description in point 3) above are poured into anapproximately 250 ml cylindrical container. The medium is then stirredvigorously (with a Dispermat® CV machine) at room temperature (20-25°C.). In the case of the siccativated resins, the siccativating agent(Durham Co 10 WM, 0.1% cobalt metal on dry binder) is added slowly andgradually with stirring (at 700 rpm) for 5 minutes. The medium is thenleft to stand for 24 hours before application.

5) Characterization Methods Used

5.1) Determination of the Tg of the Resins

The glass transition temperature Tg measurement is performed using aDSCI-700 type DSC machine from Mettler with a temperature sweep at 10°C./min from −80° C. to 150° C. and after two consecutive passages(sweeps). The Tg retained is that corresponding to the second passage(sweep).

5.2) Molecular Masses of the Resins

The measurements are taken by steric exclusion chromatography (SEC),using THF as eluent, under the following conditions:

-   -   two mixed columns D+one 100 Å column, +one 50 Å column    -   Elution with THF as the mobile phase, at 1 ml/min and at an        elution temperature of 35° C., with detection by refractive        index (RI).    -   Calibration with 11 polystyrene standards having monodisperse        molecular masses ranging from 162 to 377 400.

5.3) Evaluation of the Performance of the Novel Binders According toExamples 1 to 13 as Aqueous Dispersions

The hardness evaluation is performed on films obtained by applying to aglass plate a coat of aqueous dispersion with a wet thickness of 100 μm.These are siccativated and non-siccativated gloss varnish formulations.The siccativating agent chosen is a cobalt-based monometallic system(Durham Co 10 WM, with 0.1 weight % of cobalt metal relative to theweight of dry resin). The dispersion used as comparative reference is analkyd dispersion, which is the product Synaqua® 4804 sold by CrayValley. The performance qualities in terms of development of hardnessover time after application and of evolution of the resistance toyellowing over ageing time of the novel binders are thus compared withthose of Synaqua® 4804, taken as market reference in this field.

5.3.1) Preparation of Gloss Varnish and Paint Informations Based onDispersions Prepared According to Examples 1 to 13

Preparation of Varnish Formations

The general procedure for preparing the varnish formulations is asfollows:

150 g of aqueous binder (aqueous dispersion) prepared as above arepoured into an approximately 250 ml cylindrical container. The medium isthen stirred vigorously (with a Dispermat® CV machine) at roomtemperature (20-25° C.). FIG. 2 shows the results for the hardnessevolution and Table 5 shows the results for the yellowing evolution forthe non-siccativated varnishes.

For the siccativated varnishes, the siccativating agent is Durham Co 10WM, added at 0.1% of cobalt metal relative to the dry binder (solidscontent of the tested dispersion) slowly and gradually while stirring at700 rpm, over 5 minutes. The medium is then left to stand for 24 hoursbefore application. The results in terms of the hardness evolution forthese siccativated varnishes are presented in FIG. 1.

Preparation of the Paint Formulations

For the manufacture of a milling base, the water and the variousconstituents detailed below are placed successively in a container withstirring at high speed in a Disperlux model 2075 disperser, until afineness <10 μm is obtained.

For the manufacture of paint, the binder (tested dispersion), themilling base prepared previously, the water and the various constituentsare placed successively in a container with stirring. The siccativatingagent (Borcher Oxi-Coat) is added slowly and gradually with stirring (at700 rpm) over 5 minutes to about 1.5% for the dispersions of theinvention and 0.25% for the reference Synaqua 4804® (percentageexpressed relative to the dry binder) in order to obtain a series of drypaints that can be recoated 6 hours after application. The compositionof the paint formulation is presented below.

Composition of the Paint Formulations of Resin Dispersions of Examples 1to 13

Parts by Constituent Function weight (%) Water — 4.50 ACTICIDE MBSBiocide 0.20 DISPERBYK 190 Dispersant 0.58 BYK 022 Antifoam 0.10 TIONA595 Pigment 23.00 Total milling base 28.38 Tested dispersion — 60.50BORCHI ® OXY-COAT* Siccativating agent 0.45* Water — 8.81 AQUAFLOW ® NMS450 Thickener 0.75 AQUAFLOW ® NHS 300 Thickener 1.15 Total paint 100*amount for reference resin Synaqua ® 4804 adjusted corresponding to0.25% relative to the dry binder (solids content of the resindispersion).Characteristics of formulations (calculated by means of the formulationsoftware “PV-FORMULA Version 2-3” from Pierre Vergne—Inter DepostiDigital Number:

-   IDDM.FR.001.280022.001.S.P.2001.0003.030265):-   Volume-based pigment concentration: VPC=19%-   Solids content by weight=51.1%-   Solids content by volume=38.1%-   Density d=1.26

Comparative tests of yellowing evolution were performed on theseformulations, and the results are presented in Table 6.

5.3.2) Hardness Test: According to the Method ISO 1522

This is a Persoz hardness determined at 23° C. and at 50% relativehumidity. The varnishes are applied at a wet thickness of 100 μm and arethen dried on a perfectly horizontal surface at 23° C. and at a relativehumidity of 50% for 24 hours before the first measurement.

5.3.3) Measurement of the Yellowing: According to the Yellowing Index(Yi) Method ASTM E313-96

The yellowing measurements are taken on a Leneta 2A card with a wetthickness of 150 μm. The surface is then dried totally horizontally at23° C. and at 50% relative humidity for 24 hours before the measurementusing a Minolta CM2600D spectrocolorimeter (measurement on the whitepart of the card). The yellowing is then accelerated by placing theLeneta cards in an oven at 50° C. in the absence of light, for 15 days.

5.3.4) Blocking Resistance

The blocking resistances are determined on a Leneta 2A card with a wetthickness of 150 μm. For this test, two films of gloss paint are applied(preparation detailed in point 5.3.1) with replacement of thesiccativating agent BORCHI® OXY-COAT with Durham Co 10 WM (0.1% cobaltmetal on dry binder)) on separate Leneta cards, which are thenpositioned after 24 hours of drying at room temperature face to face sothat the paints are in contact. A weight of 50 g·cm⁻² is then placed onthe two cards that are face-to-face, exerting a pressure of 50 g·cm⁻².After 24 hours of contact, the two Leneta cards are separated andexamined. The result obtained is expressed qualitatively as a functionof the total surface area of white paint peeled off, with a note rangingfrom 0 (0=no point of peeling) to 8 (8 being the worst note with theplate highly degraded).

6) Results for Development of Hardness, Resistance to Yellowing andBlocking Resistance for Coatings Based on Aqueous Dispersions Obtainedfrom the Resins According to Examples 1 to 13

The results as regards the development of hardness are presented inFIGS. 1 and 2, respectively, for siccativated and non-siccativatedvarnishes.

The results as regards the yellowing on varnishes whose formulation isspecified in point 5.3.1) without siccativating agent are presented inTable 5 for the binders not requiring any siccativating agent in orderto dry (touch-dry<24 hours) and having an oil length up to 15% (resinsfrom Examples 1 to 9).

The yellowing results for all of the binders of the invention for asiccativated gloss paint formulation, as described in point 5.3.1), arepresented in Table 6. The content of siccativating agent is adjusted andoptimized to obtain a dry paint that can be recoated after 6 hours.

TABLE 5 Yellowing evolution of non-siccativated varnishes Synaqua ® 4804Resin Ex 1 Ex 3 Ex 4 Ex 5 Ex 6 Ex 7 Ex 8 Ex 9 (reference) Yellowing +58%+37% +58% +92% +90% +54% +115% +120% +137% evolution

TABLE 6 Yellowing evolution of gloss paints Synaqua ® 4804 Resin Ex 1 Ex2 Ex 3 Ex 4-7 Ex 8 Ex 9 Ex 10 Ex 11 Ex 12 (reference) Yellowing +58 +34+34 +80 +67 +60 +90 +75 +100 +150 evolution (%)

The capacity to cure faster for the novel aqueous binders of theinvention is even more perceptible and notable in the absence ofsiccativation (see FIG. 2). FIG. 2 illustrates the development ofhardness for the aqueous binders based on resins having the shortest oillength ranging from 0 to 15%, which means a zero oil length (0%) or anoil length ranging up to 15%, which is quite surprising given these verylow or even zero contents. In contrast, it is noted that the resins withan oil length of about 15% to 30% require the use of siccativating agentin order to develop their high hardness potential. On the other hand,good or even excellent levels of hardness may be recorded withoutsupplying siccativating agent, using resins with a low or even zero oillength (0-15%) (see FIG. 2).

In general, these novel resins show rapid development of hardness withhardness levels (at 15 days) largely superior to those of the referencedispersion Synaqua® 4804. For some of them (among the smallest oillengths), the final hardnesses reached without using siccativating agentare even identical to or greater than that of the siccativated referenceresin (4804®). This capacity to cure greatly, without necessary supplyof siccativating agent, is a major advantage in the currentenvironmental context.

Advantageously, faced with the toxicity problems experienced with cobaltsalts, these dispersions can dry with less harmful siccativating agents(which are for the majority less active when compared with theconventional cobalt-based systems) such as iron salts (BorcherOxy-Coat), vanadium or manganese salts. Much more advantageously,certain resins (0-15%) can dry and cure with high performance levelswithout the need for any siccativating agent.

Still advantageously, these resins with a greatly reduced oil length, inthe absence or presence of siccativating agent, show less yellowingevolution over time (see the details in Table 5 and 6 above) whencompared with the reference resin (Synaqua® 4804).

FIG. 1 shows the evolution over time, after application, of the hardnessof the coatings obtained for coating compositions (varnishes describedabove) in the presence of siccativating agent. The dispersions accordingto the invention have at least the same if not better performance interms of rapid growth of the hardness over time (in particular for therange of dispersions based on resins with an oil length from 0 to 15%)than that of the reference dispersion (based on Synaqua® 4804 resin)despite a higher oil length for the latter.

FIG. 2 shows even better the performance of the dispersions according tothe invention in the total absence of siccativating agent on varnishes.The reference dispersion is also represented in the presence ofsiccativating agent (0.1%) to show that the dispersions corresponding toan oil length ranging from 0 to 15%, in the absence of any siccativatingagent, show better performance (on varnishes) than the referencedispersion even when comparing the latter in the presence of 0.1%siccativating agent (comparative conditions more unfavorable for thedispersions of the invention).

Advantageously, the resins with an oil length ranging from 15% to 25%,siccativated with cobalt as described above, show excellent blockingresistance in particular relative to the reference resin (Synaqua®4804). FIG. 3 explicitly and qualitatively shows this marked differencein blocking resistance between a dispersion prepared according toExample 11 (in the left part of FIG. 3) and the reference resin(Synaqua® 4804 in the right part). Surprisingly, the resin of theinvention under these conditions does not lead to any point ofattachment or peeling of the coating during the blocking resistance test(note=0), in contrast with the reference resin (note=8). Since theapplication support for the white paint is black, this means that theblack parts of the image in FIG. 3 correspond to the parts peeled offduring the test (right part with note=8). In the case of the resindispersion according to Example 11, the white image demonstrates theabsence of any peeling (note=0).

7) Evaluation of the Resins of Zero Oil Length (“Oil Free”) or with anOil Length Ranging up to 5%, in a “coil” Two-Pack System

The resins concerned are described in Example 2 and in Examples 14 to17, which are variants of the resin of Example 2 as described above.

7.1) Preparation of Non-Water-Based Formulations for “Coil” Two-PackCoatings (Varnishes)

The solvent-based solutions (translucent) of the resins describedaccording to Examples 14 to 17 are mixed with melamine CYMEL® 303 LF inan 85/15 weight ratio (of dry resin to melamine).

FORMULATION EXAMPLE

Resin-(NVC 69.7%) 73.7 Solvarex 10 LN 8 BUTYLDIGLYCOL 8 CYMEL 303 LF 9PISA (12.5% butanol) 1.3 Total 100

The varnishes are then applied in order to have a film thickness of 20μm±2 μm on galvanized steel GARDOBOND Ref 1303 62 OE, 0.8 mm thick, andare then baked in an oven heated to 315° C. in order to reach a maximumtemperature of the support metal of 232° C. before cooling.

7.2) Evaluation of the Performance of the Binders of Zero Oil Length(“Oil-Free”) or with an Oil Length Ranging up to 5%, in a Coil Two-PackSystem

7.2.1) Methods and Tests used

a) Chemical Resistance to MEK (Methyl Ethyl Ketone).

The solvent resistance is evaluated by wearing the surface of thesamples with a pad of cotton wool soaked with MEK by performingto-and-fro motions on the coatings as described in point 7.1). The testis performed at a frequency of 60 cycles/minute (1 to-and-fro motion persecond) with a load of 1 kg on a linear abrasimeter. The time measuredcorresponds to the time for which the film of paint withstood theabrasion in the presence of the solvent.

b) Adhesion Test

The adhesion test and the grading are performed according to standardISO 2409:2007 using a 3M reference 2525 adhesive tape (adhesive power:700 cN/cm). Adhesion grading: scale from 0: good, to 5: poor. The testis repeated a second time (results presented in Table 7).

c) Adhesion Test with Collar and Ageing at 90° C.

-   1) Stamping 7 mm deep at the precise place of the adhesion test is    performed, using a Cupping Tester ELCOMETER 1620 type stamping    machine equipped with a hemispherical-shaped punch 20 mm in diameter    rising at a speed of 0.2 mm/s, on a galvanized steel plate    (dimensions 100 mm×60 mm) Covered with the coating as described in    point 7.1).-   2) The plate is then placed in an oven at 90° C. for 30 minutes.    After cooling for 30 minutes in an air-conditioned room (23°    C.±2° C. and 50%±5% RH), an adhesion test is performed according to    standard ISO 2409.

The whole test is repeated a second time, and the results are given inTable 7.

d) Hardness Test (Persoz)

Measurement of the damping of the pendulum (1 oscillation/s) accordingto NF EN ISO 1522 (cf. description of the test in point 5.3.2).

7.2.2) Results Obtained

These results are presented in Table 7 below:

TABLE 7 Results for application on galvanized steel Synolac ® Example9605 S 65 2 14 15 16 17 Chemical  80 s 140 s 140 s 100 s 120 s 170 sresistance to MEK* Adhesion 0/0 0/0 0/0 0/0 0/0 0/0 test (ISO 2409)Adhesion 2/2 0-1/0-1 0-1/0-1 0-1/0-1 0-1/0-1 0-1/0-1 test with collarand ageing at 90° C. Persoz 296 s 340 s 350 s 312 s 320 s 332 s hardness(ISO 1522) *Methyl ethyl ketone

The resin described in Example 2 and the resins according to Examples 14to 17 all lead, without exception, to very high performance in terms ofhardness, chemical resistance and adhesion to metal (galvanized steel inthe case of this application), better than those of the reference resinfor coil application (Synolac® 9605 S 65). Firstly, the adhesion isfound to be very greatly reinforced on metal by virtue of theincorporation of materials such as rosin and fatty acids (essentiallydimers) all of natural origin. The high performance recorded regardingthe hardness in a coil two-pack system confirms the substantial gain inhardness observed on the coatings (varnishes) obtained from the aqueousdispersions dried in the open air (see FIGS. 1 and 2).

1. A polyester alkyd resin, derived from at least one fatty acid and anacid component comprising, in addition to said fatty acid, from 40% to75% by weight, relative to the total weight of said resin, of rosinand/or rosin derivatives bearing at least one carboxylic acid functionwherein said resin has an oil length from 0% to 35%, and has a weightratio of oxidizable fatty monoacids relative to the overall fatty acidsfrom 0 to
 1. 2. The resin of claim 1, comprising less than 5% by weightof aromatic compound besides the optional rosin derivatives.
 3. Theresin of claim 1, wherein said acid component comprises, in addition tosaid fatty acid, said rosin and/or in addition to said rosinderivatives, at least one acid compound containing at least onecarboxylic acid function and having an overall functionality of 2 to 3,selected from the group consisting of saturated polyacids.
 4. The resinof claim 3, wherein said saturated polyacid comprises at least one C₃₆fatty acid dimer and/or C₅₄ fatty acid trimer.
 5. The resin of claim 1,wherein the oxidizable unsaturation content of said resin is from 0 to0.25 mmol of oxidizable double bonds per g of dry resin.
 6. The resin ofclaim 1, derived from an alcohol component comprising at least onepolyol of functionality ranging from 2 to
 10. 7. The resin of claim 1,having an acid number of less than 8 and a number-average molecular massMn, measured by GPC as polystyrene equivalents in THF, ranging from1,000 to 10,000.
 8. The resin of claim 1, having a Tg, measured by DSC,ranging from −40 to 50° C.
 9. The resin of claim 1, wherein said resinhas a zero oil content (0%) and said fatty acid is selected fromnon-oxidizable fatty acids with a corresponding content of oxidizableunsaturations that is 0 mmol per g of dry resin or wherein said resinhas an oil content ranging up to 5% and that, in addition to said fattyacid selected from non-oxidizable fatty acids, comprising in minorweight proportions an oxidizable fatty acid leading to said oil contentranging up to 5%.
 10. The resin of claim 9, wherein said non-oxidizablefatty acid is selected from the group consisting of saturated fattyacids and fatty acid oligomers.
 11. The resin of claim 9 wherein saidresin is derived from an alcohol component comprising glycerol oligomer,and as non-oxidizable fatty acid a C₃₆ fatty acid dimer and/or a C₅₄fatty acid trimer.
 12. An organic binder composition comprising at leastone resin of claim
 1. 13. The composition of claim 12, wherein, inaddition to the first resin of claim 1, it comprises at least one secondresin different from the first, the second resin being selected from thegroup consisting of polyester resins derived from fatty acids.
 14. Theresin of claim 2, comprising no aromatic compounds other than theoptional rosin derivatives.
 15. The resin of claim 10, wherein the saidnon-oxidizable fatty acid is selected fom the group consisting of fattyacid oligomers.
 16. The resin of claim 15, wherein said fatty acidoligomers are C₃₆ dimers and/or C₅₄ trimers.
 17. A coating compositioncomprising as binder the resin of claim
 1. 18. A coating compositioncomprising as binder the resin of claim 16.